the heads im going to be using have 13.5 degree valve angles as oppsoed to the factory 15. if i use a stock head to cut will that create an issues? im not looking to pull apart a new set of tfs heads just to flycut and i cant get a straight answer on any of my clearance questions so im looking into just cutting the pistons in case.

 

Very good question. I would assume that would bring up an issue, and I am going to be in the same boat shortly, so bump for you. lol

 

You need to use the same angle head for the fly cut. If you use a 15* to fly cut there will be no relief at the first point where the 13.5* would hit.

 

Which makes sense. Not to hijack, but can you use your good set of heads to flycut the pistons with, if you happen to have them disassembled

 

Call TFS or TEA. They should have the tool available to rent. You'll likely jack up your new heads. Either the valve seats, or the chambers.

 

You need to have the valve seats removed. Which means youd need to have new seats installed and have a new valve job done. Plus you run the risk of wearing the guides out faster. I would certainly not use a set of good heads.